remote kernel debugging

[Warner Losh]

> On Mar 28, 2015, at 10:39 AM, Manuel Stühn <freebsdnewbie at freenet.de> wrote:
> 
> On Sun, 22 Mar 2015 02:10:54 +0100, Bernd Walter wrote
>> The flags are documented in the uart manpage.
>> 0x10 flag sets the console uart and 0x80 the gdb uart.
>> 0x90 sets both.
>> But it assumes /boot/device.hints to be used, which to my knowledge isn't
>> true on the BBB.
>> The console is setup via stdin/stdout in
>> sys/boot/fdt/dts/arm/beaglebone.dts
>> No idea how gdb or any of the other flags can be entered in the DTS files.
>> 
> 
> After further investigation I found this flag for loader(8):
> 
> set hw.uart.dbgport="mm:0x48022000,br:115200" # uart1 on BBB
> 
> (more info in sys/dev/uart/uart_subr.c), which seems to be able to inform the debug-system about the desired uart-port. Unfortunately, when I'm setting this variable like shown above the systems stops right here:
> 
> Hit [Enter] to boot immediately, or any other key for command prompt.
> Booting [/boot/kernel/kernel]...
> Using DTB provided by U-Boot at address 0x80000100.
> Kernel entry at 0x80200100...
> Kernel args: (null)
> GDB: debug ports: uart
> 
> No further output appears, it seems that the whole system stopped at this point.
> 
> Any hints?

Do you have DDB, KDB and GDB all enabled in the kernel?

Warner

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